Habitat loss through vegetation clearing

While greater than 90% of the entire region is utilised for beef cattle grazing, vegetation clearing has been more focused in extent and had principally occurred on the coastal plains from Townsville south to Bowen and in extensive areas of the Belyando-Suttor sub-catchment in the south east of the region. In total 23% or 2.9 million ha of the Burdekin basin has been cleared (Queensland Herbarium 1999), with individual biogeographic subregions of the Belyando-Suttor having only 30-50% of vegetation cover remaining ( Morgan 2001 ) .

Clearing

The Burdekin Catchment has been subjected to a significant level of clearing in some areas, while other areas are less affected and only show pockets of clearing. Woodland savannas constitute the prevalent vegetation form across much of the catchment. In many areas this vegetation is still relatively intact, in others where there has been clearing activity to develop improved pastures or open up country for cropping, the native tree vegetation has been lost, and with it, it is likely that many of the biodiversity values have been lost as well ( Roth et al. 2002 ). There is a variable rate of tree clearing across the region, with some sub-catchments supporting over 90% native habitat, and others 51%.

A large portion of the coastal floodplains in the Lower Burdekin has been cleared for irrigation. Quite large tracts of land in the Belyando have also been cleared, some for cropping, some for improved pastures, and where much of the original Brigalow cover has been targeted for clearing.

In the Upper Burdekin and Desert Uplands, clearing is far less evident, although there are some significant pockets where clearing has been undertaken to enhance native pastures. Regrowth in these areas is proving to be a challenge, and the difficulty in managing regrowth coupled to marginal economic benefits has probably constrained further clearing in these areas.

The major impact of clearing includes:

• loss in species and changes in biodiversity composition and ecosystem function;

• changes to water balance, particularly groundwater with implications for dryland salinity; and

• loss of aesthetic and amenity values.